Proliferation of electronic devices utilized to transmit, receive, and manipulate date has led to problems caused by electromagnetic interference (EMI) wherein radiation from voltages induced by the proximity of signals interferes with the transmission and reception of data signals, typically in the form of digital pulses. Additionally, a need has developed to protect the solid state and other circuit devices from electrostatic discharge (ESD), that can damage or destroy the sensitive and fragile elements of solid state devices. These two developments have led to a widespread use of filters of various kinds that operate, in one case, to filter out unwanted EMI from signal transmission, and in the other case, to filter out ESD voltage transits. One widespread use has been to provide filter elements proximate to circuit boards or to cable connected to such boards within connectors. U.S. Pat. No. 4,853,659 issued Aug. 1, 1989 is drawn to a planar pi-network filter assembly that utilizes capacitors and inductors incorporated into a connector to filter out unwanted components of signals transmitted through such connector. U.S. Pat. No. 4,729,752 issued Mar. 8, 1988 is drawn to a transit suppression device incorporated into a connector including a bi-directional diode incorporated as well as a filter means that functions to provide both filter and transit protection. Reference may be had to these prior art patents for a discussion or protection against surges and a filtering of signals from connector conductors.
In the foregoing examples and in many of the filters employed for both purposes, filtering and voltage surge protection, the elements, filters and/or diodes are fabricated with the electrodes thereof soldered to connector contacts, the post portions thereof, and to ground circuits to carry off the unwanted signal components or voltage transits to ground. Because of this, care must be taken relative to the particular solders used, connectors oft times being soldered to printed circuit boards after the assembly of the filter components and the use of solder in such assembly. Additionally, for many connector designs, the physical packaging required for filters simply will not fit within the dimensional parameters of the connector, making a retrofit difficult.
Accordingly, it is an object of the present invention to provide a filter insert that can be attached to the signal and ground conductors of transmission paths, connectors or cable, to effectively filter out unwanted signal components. It is a further object to provide an add-on filter insert that may be utilized with existing connector and cable designs which drastically reduces the use of solder. It is yet a further object of the invention to provide a novel connector or cable filter insert assembly in combination and readily applicable to closely spaced signal and ground conductors in connectors or cable or the like. It is finally an object of the invention to provide an interconnection between filter elements and signal and ground connectors that readily and easily can be applied without the use of solder.